Officers from the St. Louis County police in Ferguson, Mo., on Aug. 10. (Sid Hastings/European Pressphoto Agency)

WITH PROTESTERS blocking highways and members of an armed fringe group patrolling the streets in Ferguson, Mo., you’d think authorities in St. Louis County would have something better to do than to harass a couple of journalists for doing their jobs.

This time last year, police officers in Ferguson detained The Post’s Wesley Lowery and the Huffington Post’s Ryan Reilly after a brief dust-up in a local McDonald’s. After the story gained attention online, the two were promptly released. It seemed reasonable to assume that police had figured out how foolish they would be to come down on two legitimate journalists peacefully covering a major news story.

Reasonable but, as it turns out, wrong: In a bewilderingly counterproductive decision, St. Louis County prosecutors have charged Mr. Lowery and Mr. Reilly with trespassing and interfering with a police officer, charges that could result in a $1,000 fine and a year in jail — if they weren’t bogus. The charges aren’t just counterproductive in the sense that society depends on reporters to gather facts and hold government, including law enforcement, to account. It’s counterproductive for St. Louis County authorities, who once again are displaying the sort of petty behavior that primed Ferguson’s communities for the explosion of protest that occurred last year.

Here are the facts: Journalists had been using a Ferguson McDonald’s as a staging ground to cover unrest after the shooting of black teenager Michael Brown by white police Officer Darren Wilson. Asked by officers to leave the restaurant, Mr. Lowery and Mr. Reilly apparently didn’t leave quickly enough for the police. Mr. Lowery, for one, started recording a video on his phone while he packed up, which obviously riled an officer who improperly ordered him to stop recording. On the video, the officer walks toward the exit with Mr. Lowery while the Post reporter asks legitimate questions and tries to record the interactions other officers are having with Mr. Reilly, who is not quite done packing up.

Next, there is confusion about which door Mr. Lowery is supposed to use to exit, during which he asks if he can just adjust his backpack, which, Mr. Lowery later explained, was slipping off his shoulder. At that point one of the officers says, “Let’s take him.” According to an account Mr. Lowery wrote after his arrest, the officers slammed him into a soda machine, handcuffed him and led him and Mr. Reilly to a police van. The officers refused to tell Mr. Lowery or Mr. Reilly their names.

Several officers are listed as witnesses on the court summons Mr. Lowery received. Even if they have a different story to tell, it strains the imagination to conjure a narrative consistent with the video evidence that justifies the charges the reporters now face.

Moreover, it strains any sense of discretion for St. Louis County prosecutors to seek criminal retribution against two journalists for endangering nothing except the egos of the officers involved. Tensions ran high last summer; the officers’ nerves were no doubt frayed. It amazes us that the authorities don’t leave it at that.